FreeScout is a free help desk and shared inbox built with PHP's Laravel framework. In versions 1.8.208 and below, the ThreadPolicy::edit() method contains a broken access control vulnerability that allows any authenticated user (regardless of role or mailbox access) to read and modify all customer-created thread messages across all mailboxes. This flaw enables silent modification of customer messages (evidence tampering), bypasses the entire mailbox permission model, and constitutes a GDPR/compliance violation. The issue has been fixed in version 1.8.209.